Quote: however, there was no indication of main rotor rotation at impact either on the main rotor blades or the roof surface.

Looks normal to me... when levering after the flair, you pull positive pitch to stop the descente and this stop the main rotor rotation... May be if he wasn't short he could have land his mosquito without any damage or minors ones. A roof isn't quite a good place to finish an auto but in this case he saves his life and that is the most important.

I am just a low time student and we only do power recovery autorotations (Schweizer 300.. drops like a stone ... argh ..) hence I can't say anything to rotor RPM at the end of the flair but would assume you should have at least some, since at the end of the flair you set the heli on the ground with the last energy that has remained in the rotor system, so after the skids have touched the ground the rotor is still spinning. In this case there was no energy left in that rotor system what so ever so that he probably fell the last couple of feet onto the roof.

Anyhow, you are right, the most important question is still why the engine lost power.

(11-17-2017, 05:22 PM)RotorTim Wrote: "when levering after the flair, you pull positive pitch to stop the descente and this stop the main rotor rotation..."

That is extremely dangerous. If you are in a flare and your goal is to "stop" the rotor system, what do you think will happen? Please review proper autorotation procedures before you fly again.

This is when you are going to touch the ground... You begin your flair around 15 fts then the levering and finally pitching up to slowly land and yes this slow down rotor rpm. You don't do this at 80 fts. Just common sense here.